LeapableGenerator
interface LeapableGenerator : RandomGenerator.JumpableGenerator
| java.util.random.RandomGenerator.LeapableGenerator |
This interface is designed to provide a common protocol for objects that generate sequences of pseudorandom values and can easily not only jump but also leap forward, by a large amount (ex. 2128), to a very distant point in the state cycle. Typically one will construct a series of LeapableGenerator objects by iterative leaping from a single original LeapableGenerator object, and then for each such object produce a subseries of objects by iterative jumping. There is little conceptual difference between leaping and jumping, but typically a leap will be a very long jump in the state cycle (perhaps distance 2128 or so).
Ideally, all LeapableGenerator objects produced by iterative leaping and jumping from a single original LeapableGenerator object are statistically independent of one another and individually uniform. In practice, one must settle for some approximation to independence and uniformity. In particular, a specific implementation may assume that each generator in a stream produced by the leaps method is used to produce (by jumping) a number of objects no larger than 264. Implementors are advised to use algorithms whose period is at least 2191.
Methods are provided to perform a single leap operation and also to produce a stream of generators produced from the original by iterative copying and leaping of internal state. The generators produced must implement the JumpableGenerator interface but need not also implement the LeapableGenerator interface. A typical strategy for a multithreaded application is to create a single LeapableGenerator object, calls its leaps method exactly once, and then parcel out generators from the resulting stream, one to each thread. Then the jump() method of each such generator be called to produce a substream of generator objects.
Objects that implement LeapableGenerator are typically not cryptographically secure. Consider instead using SecureRandom to get a cryptographically secure pseudo-random number generator for use by security-sensitive applications.
Summary
| Public methods | |
|---|---|
| abstract RandomGenerator.LeapableGenerator! |
copy()Returns a new generator whose internal state is an exact copy of this generator (therefore their future behavior should be identical if subjected to the same series of operations). |
| open RandomGenerator.JumpableGenerator! |
Copy this generator, leap this generator forward, then return the copy. |
| abstract Unit |
leap()Alter the state of this pseudorandom number generator so as to leap forward a large, fixed distance (typically 296 or more) within its state cycle. |
| abstract Double |
Returns the distance by which the |
| open Stream<RandomGenerator.JumpableGenerator!>! |
leaps()Returns an effectively unlimited stream of new pseudorandom number generators, each of which implements the |
| open Stream<RandomGenerator.JumpableGenerator!>! |
Returns a stream producing the given |
| open static RandomGenerator.LeapableGenerator! |
Returns an instance of |
| Inherited functions | |
|---|---|
Public methods
copy
abstract fun copy(): RandomGenerator.LeapableGenerator!
Returns a new generator whose internal state is an exact copy of this generator (therefore their future behavior should be identical if subjected to the same series of operations).
| Return | |
|---|---|
RandomGenerator.LeapableGenerator! |
a new object that is a copy of this generator |
copyAndLeap
open fun copyAndLeap(): RandomGenerator.JumpableGenerator!
Copy this generator, leap this generator forward, then return the copy.
| Return | |
|---|---|
RandomGenerator.JumpableGenerator! |
a copy of this generator object before the leap occurred |
leap
abstract fun leap(): Unit
Alter the state of this pseudorandom number generator so as to leap forward a large, fixed distance (typically 296 or more) within its state cycle.
leapDistance
abstract fun leapDistance(): Double
Returns the distance by which the leap() method will leap forward within the state cycle of this generator object.
| Return | |
|---|---|
Double |
the default leap distance (as a double value) |
leaps
open fun leaps(): Stream<RandomGenerator.JumpableGenerator!>!
Returns an effectively unlimited stream of new pseudorandom number generators, each of which implements the JumpableGenerator interface.
| Return | |
|---|---|
Stream<RandomGenerator.JumpableGenerator!>! |
a stream of objects that implement the JumpableGenerator interface |
leaps
open fun leaps(streamSize: Long): Stream<RandomGenerator.JumpableGenerator!>!
Returns a stream producing the given streamSize number of new pseudorandom number generators, each of which implements the JumpableGenerator interface.
| Parameters | |
|---|---|
streamSize |
Long: the number of generators to generate |
| Return | |
|---|---|
Stream<RandomGenerator.JumpableGenerator!>! |
a stream of objects that implement the JumpableGenerator interface |
| Exceptions | |
|---|---|
java.lang.IllegalArgumentException |
if streamSize is less than zero |
of
open static fun of(name: String!): RandomGenerator.LeapableGenerator!
Returns an instance of LeapableGenerator that utilizes the name algorithm.
| Parameters | |
|---|---|
name |
String!: Name of random number generator algorithm |
| Return | |
|---|---|
RandomGenerator.LeapableGenerator! |
An instance of LeapableGenerator |
| Exceptions | |
|---|---|
java.lang.NullPointerException |
if name is null |
java.lang.IllegalArgumentException |
if the named algorithm is not found |